Lesson 26. “After” (후에, -ㄴ/은 후에, -고 나서)

The word 후 (後) means “behind” or “after.” 

뒤 is a pure Korean word that also means “behind/after” and is sometimes interchangeably used with 후. But not always. We will learn when they’re interchangeable.

In the previous lesson, we’ve learned that the word “전 (前) ” is used with nouns and verbs to mean “ago” or “before”.

Noun + 전에 : before noun

Time Duration + 전에: (time duration) ago

Verb + 기 전에: before V-ing

후 (後) can also be used similarly, but with a slightly different structure when combined with a verb.

1. Noun 후에 : after noun

식사 후 > 식사 후에 다시 전화할게요. I will call you again after eating.

수업 후 > 수업 후에 만나자. Let’s meet after class. 

방학 후 > 방학 후에 다시 학교에 가야 돼요. I have to go to school again after school vacation.

1시 후 > 1시 후에 공항에서 친구를 만나야 돼요. – I have to meet my friend at the airport after 1 p.m.

2. Time Duration 후에 (=뒤에) :[time duration] later / from now

1시간 후(=뒤) > 1시간 후에 올게요. I will come an hour after from now.

이틀 후(=뒤) > 이틀 뒤면* 주말이에요! The weekend is two days away!
*Literally, “If it’s two days later.”

1년 후(=뒤) > 1년 후에 한국에 갈 거예요. I will go to Korea in a year.

오 분 후(=뒤) > 엄마는 오 분 뒤에 도착할 거예요. – My mom will arrive in 5 minutes.

3. Verb-ㄴ/은 후에 (=뒤에)

You add ㄴ when a verb stem ends in a vowel, and 은 when a verb stem ends in a consonant. Then you can add “후에” or 뒤에.

Verb Stem + ㄴ/은 후에 (=뒤에) = after I/he/she/they/you verb

You can simply conjugate the verb in the main clause if you want to indicate which tense the sentence is used, just like -기 전에.

한국에 온 후에 저의 한국어를 더 잘 하기 시작했어요. – After coming to Korea, I started speaking Korean better.

날씨가 걷힌 후에 밖에 갈 거에요. – I will go outside after the weather clears up.

제프한테 인사한 뒤에 자리에 앉았어요. After saying hi to Jeff, I sat at my seat.

이 집에서 20 년 동안 산* 뒤에 이사할 거예요. – After living in this house for 20 years, I will move to a new house.
*irregular : 살다 + ㄴ/은 = 산 (O) / 살은 (X) 

4. Verb-고 나서

There’s another construction you can use to mean “after you verb” and that is Verb-고 나서. You can simply add 고 나서 to a stem of a verb. There’s no irregular rules.

You can also just say, “Verb-고” and remove 나서. It would still mean “after verb-ing.”

Verb Stem + 고 (나서) : After Verb ~ing

영화를 보고 나서 잤어요. – After watching a movie, I slept.

수업 끝나고 (나서) 밥을 같이 먹자! – Let’s eat together after class.

숙제를 하고 친구를 만날 거예요. – After doing the homework, I will meet my friend.

저는 방을 청소하고 나서 저녁을 요리해야 해요. – After cleaning up my room, I have to prepare dinner.

저녁을 먹고 나서 부모님께 남자친구를 소개해드릴 거예요. – After eating dinner, I will introduce my boyfriend to my parents.

5. What are the differences between “Verb-고 나서” and “Verb-ㄴ/은 후에”?

In some textbooks, it says that in -고 나서 structure, the subject in both clauses should be the same. However, this is not necessarily true. 

For example, the following sentence would grammatically make sense, even if the subject in each clause is different. 

네가 가고 나서 (나는) 생각을 많이 해봤어. After you left, I thought about it a lot.

수업이 끝나고 나서 (저는) 화장실에 갔어요. After the class ended, I went to the bathroom.

Some textbooks also say that Verb-고 나서 can be used only when the action is complete, and that if the action is still ongoing, Verb-고 나서 cannot be used. But this is true of “Verb-ㄴ/은 후에” as well. After all, that’s what “after” means, right?

The grammar point regarding this will be explained more when we get to “More Usages of [Verb-아/어서]” lesson in Beginner 3 Course, so do rest assured for now!

The more practical differences between Verb-ㄴ/은 후에 and Verb-고 나서 are very subtle. Verb-고 나서 more means a subsequent action, so you do something “right after” you finish the previous action. Verb-ㄴ/은 후에 more means anytime after. But these two are usually interchangeable, without indicating much difference. 

Another difference would be that Verb-고 나서 sounds more casual and commonly used in spoken form compared to -ㄴ/은 후에, which sounds comparatively more formal.

So, -ㄴ/은 후에 can be interchangeably used in all the sentences we learned above using “-고 나서,” 

영화를 보고 나서 잤어요. (=영화를 본 후에 잤어요.) – After watching a movie, I slept.

수업 끝나고 (나서) 밥을 같이 먹자! (=수업 끝난 후에 밥을 같이 먹자!) – Let’s eat together after class.

숙제를 하고 친구를 만날 거예요. (=숙제를 한 후에 친구를 만날 거예요.) – After doing the homework, I will meet my friend.

저는 방을 청소하고 나서 저녁을 요리해야 해요. (=저는 방을 청소한 후에 저녁을 요리해야 해요.) – After cleaning up my room, I have to prepare dinner.

저녁을 먹고 나서 부모님께 남자친구를 소개해드릴 거예요. (=저녁을 먹은 후에 부모님께 남자친구를 소개할 거예요.) – After eating dinner, I will introduce my boyfriend to my parents.

네가 가고 나서 (나는) 생각을 많이 해봤어. (=네가 간 후에 나는 생각을 많이 해봤어.) After you left, I thought about it a lot.

수업이 끝나고 나서 (저는) 화장실에 갔어요. (=수업이 끝난 후에 저는 화장실에 갔어요.) After the class ended, I went to the bathroom.